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Wow, we have Arlene (so it begins). An impressive storm for this time of year, but by no means in this case is it relative for an active season or whatever the outcome. It's also another good opportunity on seeing a Tropical Cyclone form via atmospheric forces and not so much warm sst's.

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tatertawt24 wrote:So are we thinking this could tell us anything about the season or is it just a fluke? The only thing that gives me pause is the fact that we already had 90L at the end of March, and wasn't there another one recently? Or was that what became Arlene?

it's a medicane that formed in the Atlantic. No impact on what happens later on

Any chance this could indicate a more active subtropics? Both 1992 and 2003 had a fair number of storms there relative to the total season numbers.

not sure about that. This is basically a medicane, unrelated to later developments

tatertawt24 wrote:So are we thinking this could tell us anything about the season or is it just a fluke? The only thing that gives me pause is the fact that we already had 90L at the end of March, and wasn't there another one recently? Or was that what became Arlene?

If Arlene had formed from a wave that moved off the coast of Africa then THAT would be significant. Forming from a non-tropical low in the subtropics over cool water means nothing as far as the tropical season.

Ah, that makes a lot of sense. Thanks.

It seems that there's a lot about these off-season subtropic storms that we don't know. The way this is doing whatever it isn't supposed to despite the cool waters is very Epsilon-esque.

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Arlene has maintained a small area of deep convection surroundingthe center of the cyclone, with some of the cloud tops as cold as-50 deg C. However, satellite trends over the past couple of hoursindicate that the areal coverage of the convection has decreasedsignificantly since the 0600 UTC satellite intensity estimates, anindication that Arlene is beginning to lose its tropicalcharacteristics as the cyclone interacts with a frontal zone andalso moves over cooler water. Dvorak current intensity estimatesremain at 45 kt, and that is the intensity used for this advisory.

The initial motion estimate is now 270/27 kt. Arlene hasaccelerated westward during the past 6 hours as the cyclone movesaround the northern periphery of a larger deep-layer extratropicallow that has remained nearly stationary near 36N 48W. The smallcyclone or its remnants are expected to move in a cyclonic looparound this low for the next couple of days.

Arlene is gradually running out of space within the narrow warmsector of the aforementioned occluded low pressure system, andmerger with one or more frontal zones is likely during the next 12hours. The new official intensity forecast continues the trend ofthe previous advisory, which shows Arlene degenerating to apost-tropical cyclone by 12 hours, and dissipating by 24 hours whenthe system is expected to be absorbed into the larger barocliniclow.

Tropical storms in April are rare and Arlene is only the secondone observed in this month during the satellite era. It should benoted, however, that this type of storm was practically impossibleto detect prior to the weather satellite era.

Arlene has become embedded within the circulation of a largeextratropical cyclone, and lost most of its deep convection whilesurrounded by cold air. The post-tropical cyclone will move towardthe southwest and south at about 20 kt until dissipation latertoday.

This is the last advisory on Arlene. Additional information on thissystem can be found in High Seas Forecasts issued by the NationalWeather Service...under AWIPS header NFDHSFAT1 and WMO header FZNT01KWBC.

The final track (including remnant phase) will be interesting to see whenever the report comes out.

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